Lionel Messi trained alongside his Argentina team-mates at the Copa America Centenario Wednesday as he targets a return from injury in his team's second Group D game against Panama.

Leo Messi starts training again. AFP

Messi, who has been nursing a sore back after sustaining an injury in a friendly against Honduras last month, has trained separately under the supervision of team medical staff since arriving in the United States.

However the 28-year-old Barcelona superstar took part in a full training session on Wednesday at the University of Illinois campus, two days after sitting out Argentina's opening 2-1 victory over Chile in Santa Clara on Monday.

In a short message on his Facebook page, Messi said he hoped to make a swift return to Argentina's starting line-up.

"I hope to be ready as soon as possible to help the team," Messi wrote.

A victory against Panama on Friday would almost certainly guarantee a place in the quarter-finals for Argentina with one game remaining in Group D.

Argentina are desperate to win this year's Copa America as they aim to end a 23-year-old title drought. That barren spell has included defeats in the 2014 World Cup final and last year's Copa America final.